According to the student pilot the landing approach was conducted at 71 knots with full flaps, and the airplane was aligned with the centerline of runway 22. He noted the windsock was flat but pointing in a crosswind direction relative to the runway. He said that as he flared for landing, the wind picked up in the crosswind direction and turned the airplane into the wind. He corrected for the wind condition, but felt unsure of a safe landing. The student pilot initiated the go-around with the application of full throttle, turned off the carburetor heat, and retracted the flaps to 10 degrees. He stated that the airplane was climbing and then "just dropped and landed hard." The pilot reported that the AWOS was not reporting gusty wind conditions at the time, but the winds were from 230 degrees at less than 6 knots. According to the Cessna 150L owner's manual, "in a balked landing (go-around) climb; the wing flap setting should be reduced to 20 degrees after full power is applied. Upon reaching a safe airspeed, the flaps should be slowly retracted to full up position."